The present invention relates to a hand-held power tool, particularly a hammer drill and/or percussion hammer.
Hand-held power tools are known in the art, in which the striking mechanism includes an intermediate anvil or a drilling spindle located between a striker and a working tool. This intermediate element receives the impact energy from the striker and then strikes against the tool. The intermediate anvil of the hammer drill supports the working tool within the power tool during the operation against the pressure force applied by the operator. Axial impact damping is performed by a substantially elastic ring in the interior of the power tool, against which ring an annular shoulder of the intermediate anvil abuts, whereby the hard material of the tool is damped (so-called B-impact damping). The tool itself is in noise transmitting connection with the tool holder which guides and holds the same, so that vibrations are transmitted from the tool to the tool holder. Dust and dirt generated during the operation can unimpededly penetrate into the tool holder, and from it travel further into the interior of the power tool to the striking mechanism and the drive. The grease-lubricated or oil-lubricated inner parts of the power tool are considerably endangered. Premature damage and fast wear can take place as a result of this. The relatively expensive construction of the known power tool with the inner B-impact damping and intermediate anvil or drill spindle, is also disadvantageous. The high-loss transmission of the impact energy in the striking mechanism makes it necessary, in order to obtain required impact energy at the tool, to provide higher energy at the drive. The generation of noise is high, and takes place between the tool and tool holder on the one hand, and in inner system between the striker, intermediate anvil and tool, on the other hand. The striker has a diameter substantially corresponding to the diameter of the drive piston, whereas for example in the percussion hammer the intermediate anvil has a smaller diameter. This diameter differential leads in accordance with the theory of impact waves to additional losses during the transmission of the impact energy. With the given power, the desired high impact speed for the tool is not attained, which is required during the operation of the power tool with a relatively strong pressure. In addition to other disadvantages, the known hand-held power tool has a relatively complicated construction, and thereby is heavy, expensive and susceptible to failures.